Abstract: The invention relates to a method and means for cooling lump material in which the material in a vertical, gas-tight cooler (1) is subjected in a furst step to a transverse cooling flow (at 9) and in a second step to counter-flow cooling (at 20). Optimal cooling effect is obtained by a distribution of the cooling gas between transverse and counter-flow cooling in such a way that maximum temperature is obtained in the cooling gas leaving through the outlet (13).

Abstract: A method and an apparatus are disclosed for heating process air for industrial purposes to a predetermined temperature. In one embodiment, the method comprises passing a first air-flow portion through a plasma generator and thus heating said portion to a temperature sufficiently high to cause the ionization of nitrogen and oxygen in the portion and thus form a plasma gas, immediately thereafter adding to said plasma gas a material containing carbon and/or hydrocarbon in sufficient quantity that when said material is reacted with the plasma gas, the ratio CO+H.sub.2 /CO.sub.2 +H.sub.2 O is at least 0.1 thereby substantially avoiding the formation of nitrogen oxide; and immediately thereafter mixing with the plasma gas, with its content of material containing carbon and/or hydrocarbon, a second air flow in such proportion that the predetermined temperature is achieved in the final air mixture.

Abstract: Energy consumption may be minimized when reducing iron oxide with reducing gases which are at least partially re-circulated in the process and where the re-circulation gas is washed to remove the reaction product CO.sub.2 in what is known as a CO.sub.2 wash to enable it to be re-used, by the heat requirement necessary for regenerating the washing liquid in the CO.sub.2 wash being entirely or partially covered by the physical heat content in top gas from the shaft furnace and/or gas leaving the sponge-iron cooler of the shaft furnace.